Zillow shows not every IPO is doomed, but stock trends are showing only profitable companies need apply this year.

The last IPO to price was on Aug. 16. The company was Tudou (NASDAQ:TUDO), which is the No. 2 online video site in China. It priced its offering at $29, which was in the middle of the proposed $28-$30 range. Now, the stock price is at $23.98.

True, the deal might not be a good gauge of investor sentiment. After all, there is much skepticism about Chinese deals, especially with the concerns about alleged accounting shenanigans. Can these stocks really be trusted? After all, this year has seen a variety of high-profile scandals. Consider that top investors like John Paulson have lost hundreds of millions on these stocks.

But even if the Tudou offering is an outlier, there’s certainly many U.S. transactions that have experienced rough times. Just look at Pandora (NYSE:P), the online music provider. Coming public in June, its stock price has gone from $26 to $10.30. While the company is growing at a rapid rate, the competition has been heating up.

In fact, according to a report from Dealogic, nearly two-thirds of all 2011 IPOs are trading below their offering prices. These include Skullcandy (NASDAQ:SKUL), DemandMedia (NYSE:DMD) and Renren (NASDAQ:RENN).

Yet not all IPOs are equal. Actually, there are some big winners in the market. Then again, the companies have been growing quickly — and have shown profitability.

One example is Zillow (NASDAQ:Z). Yes, in light of the horrible residential real estate market, it seems almost impossible to see how this company can succeed. But because of its mega-brand, mobile apps and rich database, it continues to grow at a rapid clip.

In the latest quarter, Zillow’s revenues spiked 116% to $15.8 million, and it even had a $1.6 million profit. No doubt, this is the kind of stuff growth investors crave. As a result, the stock price has soared. Since coming public in mid-July at $20, the share price now is at $30.

In other words, if IPO investors are focused on profits — which does make a lot of sense — this does not bode well for companies like Groupon, as well as a variety of dot-coms that have filed for offerings recently. For example, Dealogic has reported that 215 companies have withdrawn their IPOs this year — 214 did so in 2008.

So for the remainder of the year, there might not be much action in the IPO market — that is, except for standout companies like Zynga.